52 mg of fluorescent product per mL of suspension, while in NC-RS100 and in NC-S100, the liquid portion was 333 μL/10 mL of suspension corresponding to learn more approximately 3.15 mg of fluorescent product per mL of suspension. It is important to note that the amount of rhodamine-labeled triglyceride can be increased or decreased, according to the needs of the study. The pH of the nanocapsule formulations (Table 1) was slightly acid and similar to the values previously reported for formulations prepared without the fluorescent-labeled oil [26, 29]. The size distribution profiles (Figure 5) and the D 4.3, SPAN, z-average, selleck products PDI, and zeta potential values
for the formulations containing the fluorescent product 1 (Table 1) did not differ considerably from those observed for non-fluorescent formulations [25–27]. The zeta potential values for the formulations prepared with the fluorescent product 1 (Table 1) showed values approximately closed to those previously reported for the similar formulations prepared without the dye-labeled oil [25–27]. The electrokinetic behavior of colloids is Selleckchem BIBF-1120 related to the movement of ionic solutions near charged interfaces [30]. The carboxylic acids, as pendant groups in Eudragit S100 or as terminal groups
in PCL116, are in an acid-base balance at the particle-water interface producing carboxylate functions that react with NaCl forming the electrical double layer responsible for the eletrokinetic behavior of NC-S100 and LNC-PCL. On the other hand, the NC-RS has a polymer wall of poly(ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride), whose monomer units are at 1:2:0.1 proportions. In this way, the trimethylammonioethyl moiety has a quaternary nitrogen giving to the particle-water interface a positive charge. The electrokinetic properties of NC-RS are related to the positive surface potential that those nanocapsules present after dilution
in 10 mmol L-1 NaCl aqueous solution. Considering that all formulations contain polysorbate 80, the mechanism of stabilization of those colloids is not exclusively based Dimethyl sulfoxide on the electrical repulsion of the particles since the steric hindrance effect of the surfactant plays an important role [31–33]. Then, even though the zeta potential values are near zero for all formulations, the colloidal turbid solutions have an adequate kinetic stability for the purpose of drug delivery. The NC-RS100 and NC-S100 formulations presented higher concentrations of particles (approximately 1.7-fold and 1.4-fold, respectively) than LNC-PCL (P < 0.05). This result was expected since the volumetric fraction of the dispersed phase in these formulations is higher than that of LNC-PCL, and the z-average values obtained for each formulation were similar [8]. The fluorescence spectroscopy analysis of the fluorescent nanocapsules and fluorescent lipid-core nanocapsules showed that the fluorescence property is maintained after the preparation of these formulations (Figure 6).